Can Dorico write notes in brackets?
Example see picture.
Not yet; you’ll have to fake it with Text. Hopefully we’ll see a native implementation soon, since you can already “ghost” notes in percussion staves, which is pretty much the same.
Hopefully. Although, accidentals and seconds does make brackets more complicated on polyphonic instruments, which is something a general implementation of this would need to address.
Yes, these are the small exceptions.
But it would be nice if they had a music notation program.
So wait and make so long detours.